共查询到20条相似文献,搜索用时 623 毫秒
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根据相关研究和分析来看,大功率LED散热器性能的双目标优化,主要采用的优化方法是:第一,正交试验设计法;第二,遗传算法,可以有效确定不同结构设置下的芯片结温、肋片重量,从而达到提高大功率LED散热器性能的目的.本文就大功率LED散热器性能进行概述,对大功率LED散热器性能的双目标优化进行探讨,以更好地满足大功率LED在各种应用中需求. 相似文献
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发光二极管(Light Emitting Diode,LED)作为一种场致发光光源,已经获得广泛的应用,但在影像测量中的下照明领域还处于起步和探索阶段。影像测量中,光照不均匀或者光强不适,都会影响所拍摄图像的质量。为获得高质量的图像,设计一种基于PWM数字可调的均匀光源系统,用于下照明的影像测量。系统通过正交实验法获得环形的LED阵列、灯的倾角、LED灯的数量、LED的环形直径等,搭建光源系统,使得LED环形阵列在视场2cm内获得均匀的光强,结合LED发光特性设计PWM脉冲发生电路,通过上位机的软件让均匀光源强度256级可调,适合各种不同的场合,增强实用性。实验数据表明,利用光学显微影像测量系统,在最小放大倍率0.7倍以及最大放大倍率4.5倍两种极端情况下,检测4个级别的光强均匀性都超过了83%。该系统完全能够在影像测量中达到要求。 相似文献
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研究了低能电子束辐照对发光二极管(Light emitting diode,LED)发光性能的影响。利用实验室加速器提供的电子束模拟空间电子辐射,分别对发不同颜色的光的LED进行不同剂量的辐照,并对比辐照前后的LED的电学性质及光学性质的变化。在电子束辐照下,LED的发光强度提高,同时在统计了大量LED后,发现这些LED的发光强度的离散性变好。对经电子束辐照后的LED进行电流加速老化实验,发现电子束辐照后的LED的发光强度下降趋势相比未经辐照的LED更为明显。同时利用电子束辐照机理对实验结果进行分析和讨论。 相似文献
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A novel temperature-stable light-emitting diode 总被引:2,自引:0,他引:2
A new type of light-emitting diode (LED) has been developed, the light intensity of which is stable during temperature change. This device consists of a multilayer dielectric optical filter on the surface of a conventional LED. The transmissivity of the optical filter is low for the short wavelength region of the LED's light spectrum and high for the long wavelength region. When the LED's temperature increases, the spectrum of LED light shifts toward the long wavelength side because of the shrinkage of the energy gap of the compound semiconductor. The shift increases the total transmission of the light because the transmissivity is high for the long wavelength region. This increase compensates for the decrease of the LED light intensity, which is caused by the decrease of the internal quantum efficiency. The effect of this filter is confirmed by both calculation and experiment 相似文献
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研制了一种新型LED阵列和相匹配的聚光透镜阵列构成的高亮度LED铁路信号机光学系统。进行了光学结构设计和理论计算,作了实验测试。测试结果表明,红、黄、绿、蓝和自信号机沿光轴中心光强分别大于2100、3900、2800、400和3200cd,均达到铁路信号机各项光学指标,可代替传统的以白炽灯为光源及有色玻璃螺纹聚光镜构成的铁路信号机光学系统,具有亮度高、节能和寿命长等优点。 相似文献
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Reduction of intensity of light output is one of the most common degradation modes in light-emitting diode (LED) systems. It starts from the failure of the various components in the system, including the chip, the driver, and optical components (i.e. phosphorous layer). The kinetics of degradation in real life applications is relatively slow and in most cases it takes several years to see an obvious deterioration of optical properties. Highly Accelerated Stress Testing (HAST) set-up and a methodology to extrapolate the results to real time applications are therefore needed to test the reliability of LED packages and lens materials. Using HAST concept in LED industry is inevitable due to the necessity of assessing the reliability of new products in a short period of time. This paper aims at briefly clarifying the degradation mechanisms of optical components in LED packages and explaining how they contribute to the depreciation of light output of the LED systems. The concept of HAST and the way the reliability of LED packages can be evaluated will also be discussed. 相似文献
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A 1.3 ?m-wavelength high-speed surface-emitting DH LED, with 0.6 ns rise time and 1.3 ns fall time, has been developed by optimal design of both the LED parameters and driving circuit. A 500 Mbit/s RZ pseudorandom pulse transmission experiment using the high-speed DH LED has been performed with a 5.7 dB level margin over a 2.7 km optical fibre. The 500 Mbit/s LED system feasibility has been confirmed. 相似文献